BioProject

IFNb has been used as a first line therapy for relapsing remitting multiple sclerosis (RRMS). More...

IFNb has been used as a first line therapy for relapsing remitting multiple sclerosis (RRMS). Since only a few studies have addressed the role of endogenous IFNb in the pathogenesis of the disease, our objective was to characterize its role in the transcriptional regulation of pathogenic Th17 cytokines in patients with RRMS. In-vitro studies have demonstrated that IFNb inhibited IL-17A, IL-17F, IL-21, IL-22 and IFN-b secretion in CD4+ lymphocytes through the induction of suppressor of cytokine secretion (SOCS)1 and 3. We found that patients with RRMS have increased serum and cerebrospinal fluid (CSF) Th17 (IL-17A and IL-17F) cytokine levels in comparison to the control subjects, suggesting that deficient endogenous IFNbeta secretion and/or signaling may contribute to the dysregulation of those pathogenic cytokines in CD4+ cells. We identified that the endogenous IFNb from serum of RRMS patients induced a significantly lower IFN-inducible gene expression in comparison to healthy controls (HCs). In addition, in-vitro studies have revealed a deficient endogenous and exogenous IFNb signaling in CD4+ cells derived from MS patients. Interestingly, upon inhibition of the endogenous IFNb signaling by silencing interferon regulatory factor (IRF)7 gene expression, the resting CD4+ T cells secreted significantly higher level of IL-17A, IL-17F, IL-21, IL-22 and IL-9, suggesting that endogenous IFNb suppresses the secretion of these pathogenic cytokines. In-vivo recombinant IFNb-1a treatment induced IFNAR1 and its downstream signaling molecules’ gene expression, suggesting that treatment may reconstitute a deficient endogenous IFNbeta regulation of the CD4+ T-cells’ pathogenic cytokine production in MS patients. Overall design: Gene expression changes induced by IFNβ−1a were tested using Affymetrix Human Genome U133 (HG-U133) arrays (Affymetrix) that contain 45,000 probe sets representing 39,000 transcripts derived from approximately 33,000 human genes. 107 PBMCs per condition derived from 15 CIS patients were stimulated with plate-immobilized αCD3 (1 μg/ml) and αCD28 (5 μg/ml) mAb (BD Biosciences) in the absence or presence of IFNβ-1a (1000 U/ml) (EMD Serono Inc) for 24 h in serum-free medium (Gibco). Cells were harvested and the total RNA was isolated using a Rneasy kit (Quiagen). Arrays were hybridized for 16 hours at 45oC in the GeneChip® Hybridization Oven 640 (Affymetrix). The arrays were washed and stained with R-phycoerythrin streptavidin in the GeneChip® Fluidics Station 400 (Affymetrix). The arrays were scanned with a Hewlett Packard GeneArray Scanner. Affymetrix GeneChip® Microarray Suite 5.0 software was used for washing, scanning and basic analysis. Less...